Alkoxylation process using bimetallic oxo catalyst

ABSTRACT

Alkylene oxide adducts of organic compounds having an active hydrogen are prepared by a process in which an active hydrogen reactant and an alkylene oxide reactant are reacted in the presence of a catalytically effective amount of one or more bimetallic oxo compounds of the formula (RO) n  M--O--M&#39;--O--M(OR) n , wherein each R is (independently) an optionally-substituted organic moiety, M&#39; is a divalent metal selected from the elements of Groups Va, VIa, and VIIa of the Periodic Table, each M is (independently) a trivalent or tetravalent metal, and each n is 2 if the adjacent M is trivalent of 3 if the adjacent M is tetravalent. The products are useful, for instance, as nonionic surfactants in detergent formulations. In certain preferred embodiments, the process yields a product having a very desirable distribution of alkylene oxide adducts.

This is a continuation-in-part of the application Ser. No. 666,061,filed Oct. 29, 1984, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to the preparation of reaction products ofalkylene oxides with alcohols and other organic compounds having anactive hydrogen. More particularly, this invention is directed to aprocess for such preparation employing a particular bimetallic compoundas catalyst.

A large variety of products useful, for instance, as surfactants,solvents, and chemical intermediates, are prepared by the additionreaction (alkoxylation reaction) of alkylene oxides with organiccompounds having one or more active hydrogen atoms. As an example,particular mention may be made of the alcohol ethoxylates andalkyl-substituted phenol ethoxylates prepared by the reaction ofethylene oxide with aliphatic alcohols or substituted phenols of about 8to 20 carbon atoms, which ethoxylates are common nonionic detergentcomponents of commercial cleaning formulations for use in industry andin the home. An illustration of the preparation of such an aliphalicalcohol ethoxylate (represented by formula III below) by addition of anumber (p) of ethylene oxide molecules (formula II) to a single alcoholmolecule (formula I) is presented by the equation ##STR1##

Alkylene oxide addition reactions are known to be promoted by contactwith a catalyst, conventionally a catalyst of either acidic or basiccharacter. Recognized in the art as suitable basic catalysts are thesoluble basic salts of the alkali metals of Group I of the PeriodicTable, e.g., sodium, potassium, rubidium, and cesium, and the solublebasic salts of certain of the alkaline earth metals of Group II of thePeriodic Table, e.g., calcium, strontium, and barium. Conventionalacidic alkoxylation catalysts include, broadly, the Lewis acid orFriedel-Crafts catalysts. Specific examples of these catalysts are thefluorides, chlorides, and bromides of boron, antimony, tungsten, iron,nickel, zinc, tin, aluminum, titanium and molybdenum. The use ofcomplexes of such halides with, for example, alcohols, ethers,carboxylic acids, and amines have also been reported. Still otherexamples of known acidic alkoxylation catalyts are sulfuric andphosphoric acids; the perchlorates of magnesium, calcium, manganese,nickel and zinc; metals oxalates, sulfates, phosphates, carboxylates andacetates; alkali metal fluoroborates, zinc titanate; and metal salts ofbenzene sulfonic acid.

In one important aspect, the present invention relates to analkoxylation reaction catalyzed by certain bimetallic oxo compounds.Such substances have been known in the chemical arts. Description ofthese and related compounds are described, for instance, in U.S. Pat.No. 3,432,445, Belgian Pat. No. 680,456, U.S. Pat. Nos. 3,607,7854,281,087, 4,419,482, and 3,576,762, and in the publication of Ph.Teyssie et al entitled "Catalysis with Soluble M--O--M'--O--M BimetallicOxides (Chemtech., Mar. 1977, p. 193). The bimetallic oxo compounds havenot, however, been recognized as useful in promoting alkoxylationreactions.

In other aspects, the invention further involves the discovery of aprocess for the production of alkylene oxide adducts (alkoxylates)characterized by a narrow alkylene oxide adduct distribution. Alkyleneoxide addition reactions are known to produce a product mixture ofvarious alkoxylate molecules having a variety of alkylene oxide adducts,(oxyalkylene adducts), e.g., having different values for the adductnumber p in formula III above. The adduct number is a factor which inmany respects controls the properties of the alkoxylate molecule, andsubstantial effort is often devoted to tailoring the adduct numberdistribution of a given product mixture to its intended service. Incertain preferred aspects, the present invention is a processcharacterized by enhanced selectivity for the preparation of alkoxylatemixtures in which a relatively large proportion of the alkoxylatemolecules have a number (p) of alkylene oxide adducts that is within arelatively narrow range of values. It is known that alkoxylate productshaving such a narrow range distribution are preferred for use indetergent formulations (Great Britain Pat. No. 1,467,134; DerwentPublications Research Disclosure number 194,010). Narrow-rangealkoxylates are also known to be particularly valuable as chemicalintermediates in the synthesis of certain carboxyalkylated alkylpolyethers (U.S. Pat. No. 4,098,818) and of certain alkyl ether sulfates(Great Britain Pat. No. 1,553,561).

Attempts made in the prior art to produce alkoxylates having a morenarrow-range distribution of alkylene oxide adducts have centered uponprocesses for the preparation of alcohol alkoxylates, and mostparticularly upon the preparation of ethylene oxide adducts of higher(C₈ to C₂₀) aliphatic primary alcohols. The common conventional basiccatalysts, i.e., compounds of the alkali metals, are known to beresponsible for the production of alcohol ethoxylates having arelatively broad distribution. Conventional acid-catalyzed alkoxylationcatalysts have long been recognized to produce alcohol ethoxylateproducts having a narrow distribution of alkylene oxide adducts.However, acid catalysis is known to have substantial disadvantage inseveral respects. For instance, the acids are often unstable, withlimited life and effectiveness as catalysts in the ethoxylation mixture.Both the catalysts themselves and their decomposition products catalyzeside reactions producing relatively large amounts of polyethyleneglycols, and also react directly with the components of the alkoxylationmixture to yield organic derivatives of the acids. Overall, use of acidethoxylation catalysts is known to result in relatively poor qualityproducts.

A great deal of attention has recently been given in the art toprocesses which utilize basic compounds of the alkaline earth metals ascatalysts for the preparation of alcohol alkoxylate products having arelatively narrow-range distribution. For instance, it has recently beenreported (U.S. Pat. Nos. 4,210,764, 4,223,164, 4,239,917, 4,453,022,4,453,023, 4,302,613, and 4,375,564 and the published European PatentApplications Ser. Nos. 0026544, 0026546, 0026547, 0085167 and 0092256)that alkoxylation promoted by basic barium, strontium, calcium andmagnesium compounds, either alone or with specified co-catalysts, yieldsan alkoxylate having a distribution which is more narrow or peaked thanthat of the product of an alkoxylation promoted by basic compounds ofthe Group I metals. Such products are still, however, considered to beless than optimal from the standpoint of overall product quality,requirements for catalyst removal, and/or narrowness of productdistribution.

Other recent disclosures of related alkoxylation processes include U.S.Pat. No. 4,456,697, which reports the use of a catalyst combining HF anda metal or mixed metal alkoxide of the formula M(OC_(n) H_(2n+1))qwherein M is selected from the group consisting of aluminum, gallium,indium, thallium, zirconium, hafnium, and titanium as well as U.S. Pat.No. 4,375,564 which describes catalysts combining a magnesium compoundwith a compound of an element selected from the group consisting ofaluminum, boron, zinc, titanium, silicon, molybdenum, vanadium, gallium,germanium, yttrium, zirconium, niobium, cadmium, indium, tin, antimony,tungsten, hafnium, tantalum, thallium, lead, and bismuth.

SUMMARY OF THE INVENTION

It has now been found that certain bimetallic oxo compounds are usefulas catalysts for the addition reaction of alkylene oxides with alcoholsand other organic compounds having one or more active hydrogen atoms.

Accordingly, in the broad sense, the invention is a process for thepreparation of alkoxylates of active hydrogen containing compounds,which comprises contacting an alkylene oxide reactant (e.g., ethyleneoxide, propylene oxide, etc.) with an active hydrogen reactant (e.g.,one or more alcohols, phenols, thiols, amines, polyols, or carboxylicacids) in the presence of a catalyst comprising one or more bimetallicoxo compounds of the formula

    (RO).sub.n M--O--M'--O--M(OR).sub.n

wherein R (individually in each occurrence) represents anoptionally-substituted organic moiety, M' represents a divalent metalselected from those of Groups Va, VIa, and VIIa of the Periodic Table, Mrepresents (individually in each occurrence) either a trivalent metal ora tetravalent metal, and n is 2 if the adjacent M is a trivalent metalor 3 if the adjacent M is a tetravalent metal.

It has further been found that the use of such bimetallic oxo compoundsas alkoxylation catalysts provides a process for the preparation of analkoxylate product, particularly an alkanol ethoxylate product, havingan exceptionally narrow-range alkylene oxide adduct distribution. Thisproduct is of high quality (relatively free of by-products) and ischaracterized by a distribution which is notably more narrow or peakedthan that of products of conventional alkoxylation reactions catalyzedby basic compounds of either the alkali metals or the alkaline earthmetals.

BRIEF DESCRIPTION OF THE DRAWING

The attached drawing represents, in its one FIGURE, a representativeplot of the distribution of alkylene oxide adducts in products preparedby reaction of ethylene oxide with C₁₂ and C₁₃ primary liner aliphaticalcohols in the presence of each of three different catalysts. The curvedesignated A represents the typical distribution of a product preparedusing a conventional basic alkali metal alkoxylation catalyst,specifically KOH; curve B represents the typical distribution of aproduct prepared using a conventional basic alkaline earth metalalkoxylation catalyst, specifically barium hydroxide; and curve Crepresents the distribution of a product prepared under practice inaccordance with the invention. In each case, the alkoxylate productexhibits a peak in its distribution at an adduct number in the rangefrom about 1.7 to 1.9.

The drawing will be further described in the Examples of the inventionwhich follow.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention centers upon discoveries associated with the usein an alkoxylation process of a certain class of catalysts. Apart fromthe use of such catalysts, the process of the invention is, as a generalrule, suitably conducted using such reactants and practicing under suchprocessing procedures and reaction conditions as are known to the art ofalkoxylation reactions. Certain preferences may, however, be expressedfor particular reactants, procedures and conditions.

Thus, for instance, the invention is generally applicable to processesutilizing any alkylene oxide (epoxide) reactant containing one or morealkylene oxides having from two to about 20 carbon atoms. Specificexamples of alkylene oxides suitable for use in the alkoxylation ofactive hydrogen containing compounds are well known in the art.Preference generally exists for the use of the lower, e.g., C₂ to C₈alkylene oxides and for the use of the vicinal alkylene oxides. From thestandpoint of commercial interest, specific mention may made of the C₂to C₄ vicinal alkylene oxides, including ethylene oxide, propyleneoxide, and the 1,2- and 2,3-butylene oxides. Particularly preferred areethylene oxide and propylene oxide, while use of ethylene oxide isconsidered most preferred. Mixtures of alkylene oxides are suitable, inwhich case the product of the invention will be a mixed alkoxylate.

Likewise, the active hydrogen reactants suitably utilized in the processof the invention include those known in the art for reaction withalkylene oxides and conversion to alkoxylate products. The suitableclasses of active hydrogen reactants include, but are not necessarilylimited to alcohols, phenols, thiols (mercaptans), amines, polyols,carboxylic acids, and mixtures thereof.

Among the suitable carboxylic acids, particular mention may be made ofthe mono- and dicarboxylic acids, both aliphatic (saturated andunsaturated) and aromatic. Specific examples include acetic acid,propionic acid, butyric acid, valeric acid, caproic acid, lauric acid,myristic acid, palmitic acid, steric acid, oleic acid, rosin acids, talloil acids, terephthalic acid, benzoic acid, phenylacetic acid, toluicacid, acrylic acid, methacrylic acid, cotonic acid, maleic acid, and thelike.

Among the suitable amines, particular mention may be made of primary,secondary and tertiary alkylamines and of alkylamines containing bothamino and hydroxyl groups, e.g., N,N-di(n-butyl)-ethanolamine andtripropanolamine.

Among the suitable thiols, particular mention may be made of primary,secondary and tertiary alkane thiols having from 1 to about 30 carbonatoms, particularly those having from about 8 to 20 carbon atoms.Specific examples of suitable tertiary thiols are those having a highlybranched carbon chain which are derived via hydrosulfurization of theproducts of the oligomerization of lower olefins, particularly thosedimers, trimers, and tetramers and pentamers of propylene and thebutylenes. Secondary thiols are exemplified by the lower alkane thiols,such as 2-propanethiol, 2-butanethiol, and 3-pentanethiols, as well asby the products of the hydrosulfurization of the substantially linearoligomers of ethylene as are produced by the Oxo process.Representative, but by no means limiting, examples of thiols derivedfrom ethylene oligomers include the linear carbon chain products, suchas 2-decanethiol, 3-decanethiol, 4-decanethiol, 5-decanethiol,3-dodecanethiol, 5-dodecanethiol, 2-hexadecanethiol, 5-hexadecanethiol,and 8-octadencanethiol, and the branched carbon chain products, such as2-methyl-4-tridecanethiol. Primary thiols are typically prepared fromterminal olefins by hydrosulfurization under free-radical conditions andinclude, for example, 1-butanethiol, 1-hexanethiol, 1-dodecanethiol,1-tetradecanethiol and 2-methyl-1-tridecanethiol.

Among the polyols, particular mention may be made of those having from 2to about six hydroxyl groups. Specific examples include the alkyleneglycols such as ethylene glycol, propylene glycol, hexylene glycol, anddecylene glycol, the polyalkylene glycol ethers, such as diethyleneglycol, triethylene glycol, propylene glycol, dipropylene glycol, andtripropylene glycol, glycerine, sorbitol, and the like.

The alcohols and phenols are today the principal reactants in commercialalkoxylate production and are preferred classes of active hydrogenreactants for purposes of the invention. Among the phenols, particularmention may be made of phenol and of alkyl-substituted phenols whereineach alkyl substituent has from one to about 30 (preferably from one toabout 20) carbon atoms, for example, p-methylphenol, p-ethylphenol,p-hexylphenol, p-decylphenol, didecyl phenol and the like.

Acyclic aliphatic alcohols form a most preferred class of reactants. Inthis regard, it is found that the aliphatic alcohols benefit to arelatively great degree from the capabilities of the invention for thepreparation of alkoxylates having narrow-range or peaked alkylene oxideadduct distributions. This is particularly true for the primarymono-hydric aliphatic alcohols, although secondary and tertiary alcoholsas well as polyhydric alcohols are also very suitably utilized in theprocess of the invention. Preference can also be expressed, for reasonof both process performance and commercial value of the product, foraliphatic alcohols having from one to about 30 carbon atoms, with C₆ toC₂₄ alcohols considered more preferred and C₈ to C₂₀ alcohols consideredmost preferred. As a general rule, the aliphatic alcohols may be ofbranched or straight chain structure, although preference further existsfor alcohol reactants in which greater than about 50 percent, morepreferably greater than about 60 percent and most preferably greaterthan about 70 percent of the molecules are of linear (straight-chain)carbon structure.

Specific examples of primary straight-chain monohydric aliphaticalcohols include ethanol, hexanol, octanol, dodecanol, pentadecanol,octadecanol and eiscosanol. Specific examples of branched chain orsecondary alcohols include isopropanol, isoheptanol, 3-heptanol,isodecanol, 2-methyl-1-nonanol, 2-methyl-1-undecanol, 4-tetradecanol,and 4-hexadecanol.

Mixtures of active hydrogen reactants in general and mixtures ofalcohols in particular are suitable for purposes of the invention andare often preferred for reasons of their commercial availability.Mixtures of higher (e.g., C₈ to C₂₀) monohydric acyclic aliphaticalcohols are known to be commercially prepared, for instance, byhydroformylation of olefins or by reduction of naturally occurring fattyesters. Specific examples of commercially available alkanol mixtures inthe C₉ to C₁₈ range are the NEODOL detergent alcohols, trademark of andmanufactured by Shell Chemical Company, e.g., the products identified asNEODOL 91 alcohols (predominantly in the C₉ to C₁₁ range), NEODOL 23alcohols, (predominantly C₁₂ and C₁₃ alcohols), NEODOL 25 alcohols(predominantly C₁₂ to C₁₅), and NEODOL 45 alcohols (predominantly C₁₄and C₁₅).

Further general and specific illustrations of suitable alkoxylationprocess reactants, both the alkylene oxide reactants and the activehydrogen reactants, are provided by the above-referenced patents andpublished patent applications, the relevant teachings of which areincorporated herein for that purpose.

For purposes of the invention, the alkylene oxide reactant and theactive hydrogen reactant are necessarily contacted in the presence ofthe specified bimetallic oxo catalyst. Such materials are known to theart and are conventionally represented by the formula

    (RO).sub.n M--O--M'--O--M(OR).sub.n.

M in the above formula represents (individually in each occurrence)either a trivalent metal or a tetravalent metal. Preferably, each M isindependently selected from the group consisting of aluminum, titanium,boron, vanadium, scandium, germanium, yttrium, zirconium, tin, lanthanumand other members of the lanthanide series, hafnium, tantalum tungsten,palladium, and antimony. More preferably, each M is selected from thegroup consisting of aluminum, titanium, boron and vanadium, and mostpreferably each M is either aluminum or titanium.

M' in the above formula represents a divalent metal selected from thosedivalent metals of the Groups Va, VIa, and VIIa of the Periodic Table(i.e., the elements of atomic number 23-25, 41-43, and 73-75). M' ispreferably selected from the group consisting of rhenium, vanadium,chromium, molybdenum, manganese, and tungsten, and is more preferablyselected from the group consisting of vanadium, molybdenum, manganese,and tungsten. Most preferred as the M' metal are molybdenum andvanadium. Certain of the metals, e.g., vanadium, may have multiplevalence states which make them suitable for use as the metal M, themetal M', or for both M and M'.

The R substituents in the above formula individually and independentlyrepresent any organic or substituted organic group, preferably ahydrocarbyl group and more preferably an alkyl group. The carbon numbersof the R substituents are not critical aspects of the invention,although preference may be expressed for R substituents each having fromone to about 30 carbon atoms, most particularly from one to about 20carbon atoms. Catalysts with lower alkyl (e.g., C₁ to C₆) R groups aremost easily prepared and are very suitable for use in the invention. Theuse of catalysts having R substituents with carbon numbers in theseranges facilitates a homogeneous reaction mixture in which the catalystis soluble in the active hydrogen containing reactant. It is notnecessary, however, that the reaction involve homogeneous catalysis forpurposes of the invention. In this regard one or more of the Rsubstituents may suitably be of higher carbon number and/or the catalystmay be supported on a solid carrier, for example, silica, alumina, or asilica/alumina mixture, to produce a heterogeneous catalyst.

The subscripts n in the formula designate the number of OR groups boundto each M. If the adjacent M atom is trivalent n is 2, and if theadjacent M atom is tetravalent n is 3. It is to be emphasized that inany one bimetallic oxo molecule the two M atoms may be different, forexample, one a trivalent metal and the other a different trivalent metalor a tetravalent metal. Likewise, the several R substituents in any onemolecule may be the same or different organic radicals.

Methods for the preparation of bimetallic oxo compounds suitable for usein the invention are described in the aforementioned U.S. Pat. Nos.3,432,445, 3,607,785, 4,281,087, and publication Chemtech, March 1977,p. 193, the relevant teachings of which patents and publication areincorporated herein by this reference. A very convenient method forpreparation of such a compound in which R represents an alkyl radicalinvolves the reaction of two mols of trivalent and/or tetravalent metal(M) alkoxide with one mol of the acetate of a divalent metal (M'), forinstance, at elevated temperature (e.g. 200° C.) and in the presence ofa solvent (e.g., tetralin):

    2(RO).sub.n+1 M+M'(OAc).sub.2 →(RO).sub.n M--O--M'--M(OR).sub.n +2 ROOAC

If desired, the bimetallic oxo compounds may be prepared with one set ofR groups and then one or more different R group(s) substituted into themolecule by alcoholysis reaction.

The bimetallic oxo compound is present in the reaction mixture in acatalytically effective amount, typically at least about 0.01% w(percent by weight), based on the active hydrogen reactant. Althoughcatalyst quantity is not narrowly critical, preference may be expressedfor use of the catalyst in amount of at least about 0.1% w, while anamount between about 0.2 and 1.0% w is considered most preferred.Substantially greater quantities of bimetallic oxo catalyst, e.g., 10 or20% w, are very suitable and may be useful for applications involvingheterogeneous catalysts.

In terms of processing procedures, the alkoxylation reaction in theinvention may be conducted in a conventional manner. The active hydrogenreactant and the bimetallic oxo compound are very convenientlyintroduced into a reactor, followed by addition of that quantity of thealkylene oxide reactant necessary to produce an alkoxylate product ofthe desired mean or average adduct number, e.g., typically from lessthan one to about 30. In general terms, suitable and preferred processtemperatures and pressures for reactions utilizing the bimetallic oxocatalysts are the same as in conventional alkoxylation reactions,between the same reactants, employing conventional catalysts. Atemperature of at least about 60° C., particularly at least about 100°C., is typically necessary for a significant rate of reaction, while atemperature less than about 250° C., particularly less than about 200°C., and most particularly less than about 170° C., is typicallynecessary to minimize degradation of the product. Superatmosphericpressures are preferred for processes involving the lower (particularlyC₂ to C₄) alkylene oxide reactants. While these procedures describe abatch mode of operation, the invention is equally applicable to acontinuous process.

When the preferred C₆ to C₂₄ alkanols or the preferred alkyl-substitutedphenols and the preferred C₂ to C₄ vicinal alkylene oxides are appliedas reactants in the process of the invention, the alkoxylation reactionis preferably carried out at a temperature in the range from about 130°to 200° C., while a temperature between about 150° and 190° C. is stillmore preferred. Considered most preferred is a reaction temperature inthe range from about 165° to 175° C. A total pressure in the range fromabout 10 to 150 psig is usually preferred for the reaction between suchhigher alkanols or substituted phenols and lower alkylene oxides. Thealkanol or phenol reactant is generally a liquid and the alkylene oxidereactant is generally a vapor for such reactions. Alkoxylation is thesuitably conducted by introducing gaseous alkylene oxide into a pressurereactor containing the liquid alkanol. Catalyst is very conveniently insolution in, or otherwise mixed with, the alkanol. For considerations ofprocess safety, the partial pressure of the lower alkylene oxidereactant is preferably limited, for instance, to less than about 60psia, and/or the reactant is preferably diluted with an inert gas suchas nitrogen, for instance, to a vapor phase concentration of about 50percent or less. The reaction can, however, be safely accomplished atgreater alkylene oxide concentration, greater total pressure and greaterpartial pressure of alkylene oxide if suitable precautions, known to theart, are taken to manage the risks of explosion. A total pressure ofbetween about 40 and 110 psig, with an alkylene oxide partial pressurebetween about 15 and 60 psig, is particularly preferred, while a totalpressure of between about 50 and 90 psig, with an alkylene oxide partialpressure between about 20 and 50 psig, is considered more preferred.

The alkoxylate prepared in the process of the invention is typically aproduct of very acceptable quality, having a relatively low content ofpolyalkylene glycols and other by-products. Unlike the products oftypical acid or base catalyzed reactions of the prior art, the productof the invention is of essentially neutral pH. The bimetallic oxocompounds do not impart significant acidic or basic character to thereactants or to the product. Accordingly, it is not necessary, as inconventional practice, to neutralize the alkoxylate product by additionof base or acid. In this regard, the neutral pH of the process isconsidered to be a further desirable feature of the invention from thestandpoint of product quality.

The high quality of the product, particularly in terms of the highselectivity of the process to the preparation of the desired adducts, isconsidered to be a surprising aspect of the invention, in view ofrecognition in the art of the use of like bimetallic oxo catalyst topromote the polymerization of alkylene oxides. In the aforementionedpublication of Teyssie et al in Chemtech, March, 1977, p. 192, it isreported, for instance, that bimetallic oxo catalysts promote thepolymerization of alkylene oxides, even when the reaction mixturecontains active hydrogen compounds such as alcohols. Alkylene oxidepolymers, also known as polyalkylene glycols, are generally known to bethe major undesirable by-products of alkoxylation processes. For thisreason, it is not predictable that catalysts recognized for theiractivity in promoting polymerization of alkylene oxides would besuitable for use as alkoxylation catalysts.

The production of an alkylene oxide polymer upon contact of an alkyleneoxide, a bimetallic oxo catalyst and an alcohol, as described in thecited publication of Teyssie et al, is considered to be attributable tothe presence in the reaction mixture of a liquid solvent, e.g., asaturated hydrocarbon solvent such as n-heptane. It is not intended thatthe present invention be carried out in the presence of any such addedmaterial, acting as a liquid reaction solvent, which has any meaningfulinfluence upon the reactivity of the alkylene oxide and active hydrogenreactants, in the presence of the bimetallic oxo catalyst.

Thus, for example, if the process is one involving the contact andreaction in a reaction zone comprising a vapor phase lower alkyleneoxide reactant (i.e., a C₂ to C₄ vicinal alkylene oxide, particularlyethylene oxide, propylene oxide, or mixtures thereof), and a liquidphase higher (e.g., C₆ to C₂₄) acyclic aliphatic alcohol, the liquidphase is preferably essentially solvent-free, that is essentially freeof a hydrocarbon or other added solvent which adversely influences thealkoxylation reaction or promotes any other competing reaction involvingthe alkylene oxide and/or the alcohol. More preferably, the liquid phaseof such a reaction zone is essentially solvent-free and consistsessentially of the alcohol, the catalyst, and (once the alkoxylationreaction has commenced) the alkoxylate product. Most preferably, theliquid phase in such a reaction zone is solvent-free and consists of thereactants, the catalyst, and the product (together with minor amounts ofimpurities which may inherently be present in the alcohol and catalyst,minor amounts of inert gas components in solution in the alcohol andalkoxylate, and minor amounts of by-products (e.g., polyalkyleneglycols) which are produced along with the desired alkoxylate).

The following Examples and Comparative Experiments are provided tofurther illustrate certain specific aspects of the invention but are notintended to limit its broader scope.

EXAMPLE 1

An alkoxylation process in accordance with the invention was carried outusing a bimetallic (molybdenum and aluminum) oxo catalyst. The catalystwas prepared by dissolving a mixture of 3 grams (0.007 mols) ofanhydrous molybdenum acetate and 5.72 grams (0.028 mols) of aluminumisopropoxide in 100 ml tetralin, and heating the resulting solution at200° C. for 18 hours. After cooling to 25° C. the solvent was removed byevaporation under vacuum to produce 7.9 grams of a black powder. Thispowder was dissolved in toluene producing a black solution containing20% w bimetallic oxo catalyst in toluene.

The active-hydrogen reactant for the alkoxylation was a NEODOL 23Alcohol (trademark of and sold by Shell Chemical Company), characterizedas a mixture of primary, 80% linear (20% branched), aliphatic alcoholscontaining twelve and thirteen carbon atoms (about 45% C₁₂, 55% C₁₃).Initially, the liquid alcohol reactant was dried by heating under anitrogen sparge at 130° C. for one hour. Then, 5 grams of the 20% wsolution of the molybdenum and aluminum bimetallic oxo catalyst intoluene prepared as described above was added to the alcohol at 100° C.and the mixture was heated to 130° C. and maintained at that temperatureand under nitrogen sparge for an additional hour.

The catalyst and alcohol mixture was transferred to an autoclave reactorwhich was then sealed, heated to 170° C. and pressured to 70 psig with amixture of ethylene oxide in nitrogen (40% ethylene oxide by mol). Thereaction commenced without an induction period. Temperature in theautoclave was maintained at 170° C. and ethylene oxide was added to thereactor system, upon demand, to maintain the 70 psig pressure. About 27grams of ethylene oxide reacted over a 3 hour period. The reactor wasthe maintained at 170° C. for an additional 30 minutes without furtheraddition of ethylene oxide, to consume unreacted ethylene oxide in thesystem. The product was analyzed by combined GC/LC and found to have anaverage ethylene oxide adduct number (mols ethylene oxide reacted,divided by total mols of alcohol) of 1.9 and to contain 2% wpolyethylene glycols (PEG). The distribution of the various adducts inthe alkoxylate product of this Example is presented in the Table below.

EXAMPLE 2

The procedures of Example 1 were repeated, with addition of 11 grams ofethylene oxide over a 1 hour period, for the preparation of a producthaving an average ethylene oxide adduct number of 0.9. The productcontained 1.2% w PEG. Adduct distribution is presented in the Table.

EXAMPLE 3

The procedures of Example 1 were again followed, with addition of 21grams of ethylene oxide over a 2 hour period, for the preparation of aproduct having an average ethylene oxide adduct number of 1.7. Theproduct contained 3.5% PEG. Adduct distribution data is presented in theTable below. The distribution of the various adducts in the alkoxylateproduct of this Example is presented in the Table below and illustratedby Curve C in the attached drawing.

COMPARATIVE EXPERIMENTS

Experiments were also conducted under comparable procedures andconditions, but utilizing conventional catalysts and thus not inaccordance with the invention. In one experiment, a potassium hydroxidecatalyst was used to prepare an ethoxylate of the NEODOL 23 Alcoholreactant, having an average ethylene oxide adduct number of about 1.9.The adduct distribution is presented in the following Table and alsoindicated by curve A in the attached drawing.

In another experiment, a barium hydroxide catalyst and the samereactants were used to prepare a product having an average adduct numberof about 1.7. The distribution is shown in the Table by curve B of thedrawing.

                  TABLE                                                           ______________________________________                                        CATALYST                                                                              Mo.sup.+2 /Al.sup.+3                                                          bimetallic oxo                                                        Adduct  catalyst                                                              Number  Example  Example  Example                                             P       1        2        3      K.sup.+                                                                              Ba.sup.+2                             ______________________________________                                        0       10.7% w  33.7% w  13.3% w                                                                              28.9% w                                                                              29.5% w                               (unreacted                                                                    alcohol)                                                                      1       23.6     39.1     28.9   13.1   12.9                                  2       26.3     18.5     27.4   13.2   15.8                                  3       20.5      6.0     16.4   11.5   15.8                                  4       11.6      1.9      7.6    8.9   12.3                                  5        4.8      0.5      3.0    6.5    7.3                                  6        1.4      0.3      1.3    4.8    3.4                                  7        0.9      0.0      0.9    3.5    1.8                                  8        0.2               0.8    2.6    0.7                                  9        0.0               0.4    2.0    0.3                                  10                                1.4    0.1                                  11                                1.1                                         12                                0.7                                         13                                0.6                                         14                                0.4                                         15                                0.3                                         ______________________________________                                    

I claim as my invention:
 1. A process for the preparation of alkyleneoxide adducts of acyclic aliphatic alcohols which comprises contactingand reacting an alkylene oxide reactant selected from the groupconsisting of C₂ to C₄ vicinal alkylene oxides with one or more acyclicaliphatic alcohols in the presence of a catalytically effective amountof a bimetallic oxo compound of the formula (RO)_(n)M--O--M'O--M(OR)_(n), wherein each R is a hydrocarbyl group, M' is adivalent metal selected from the group consisting of elements of GroupsVa, VIa, and VIIa of the Periodic Table, each M is a trivalent metal ora tetravalent metal, and each n is 2 if the adjacent M is a trivalent of3 if the adjacent M is tetravalent, in a reaction zone having a liquidphase which comprises that said alcohols and is essentially free ofadded reaction solvent.
 2. The process of claim 1, wherein M is atrivalent or tetravalent metal selected from the group consisting ofaluminum, titanium, boron, vanadium, scandium, germanium, yttrium,zirconium, tin, lanthanum and other members of the lanthanide series,hafnium, tantalum, tungsten, palladium, and antimony.
 3. The process ofclaim 2, wherein each M' is a divalent metal selected from the groupconsisting of vanadium, rhenium, chromium, molybdenum, tungsten, andmanganese.
 4. The process of claim 3, wherein each R is a C₁ to C₃₀hydrocarbyl moiety.
 5. The process of claim 4, wherein each R is analkyl moiety, M' is selected from the group consisting of vanadium,molybdenum, manganese, and tungsten, and each M is selected from thegroup consisting of aluminum, titanium, boron and vanadium.
 6. Theprocess of claim 4, wherein each R is C₁ to C₂₀ alkyl moiety, M' isselected from the group consisting of vanadium, molybdenum, manganese,and tungsten, and each M is selected from the group consisting ofaluminum, titanium, boron and vanadium.
 7. The process of claim 6,wherein each R is a C₁ to C₆ alkyl moiety.
 8. The process of claim 6,wherein the alkylene oxide reactant is selected from the groupconsisting of ethylene oxide, propylene oxide and mixtures thereof. 9.The process of claim 8, wherein the alcohols are C₆ to C₂₄ primaryalcohols.
 10. The process of claim 9, wherein the alcohols are C₈ to C₂₀alcohols and the alkylene oxide reactant is ethylene oxide.
 11. Theprocess of claim 1, wherein the liquid phase in the reaction zone issolvent-free and consists essentially of the alcohol, the catalyst, andthe alkylene oxide adduct product.
 12. The process of claim 11, whereinthe alkylene oxide reactant is ethylene oxide, the alcohols are C₈ toC₂₀ primary alcohols, each R is a C₁ to C₂₀ alkyl moiety, M' is selectedfrom the group consisting of vanadium, molybdenum, manganese, andtungsten, and each M is selected from the group consisting of aluminum,titanium, boron, and vanadium.
 13. The process of claim 1, wherein thebimetallic oxo compound is supported on a carrier.
 14. The process ofclaim 12, wherein the bimetallic oxo compound is supported on a carrier.15. A process for the preparation of ethylene oxide adducts of acyclicaliphatic primary alcohols which comprises contacting and reactingethylene oxide with one or more C₈ to C₂₀ monohydric acyclic aliphaticprimary alcohols in the presence of a catalytically effective amount ofa bimetallic oxo compound of the formula (RO)_(n)M--O--M'--O--M(OR)_(n), wherein each R is a C₁ to C₂₀ alkyl moiety, M'is a divalent metal selected from the group consisting of vanadium,molybdenum, manganese and tungsten, each M is a trivalent or tetravlentmetal selected from the group consisting of aluminum, titanium, boronand vanadium, and each n is 2 if the adjacent M is trivalent or 3 if theadjacent M is tetravalent, in a reaction zone which comprises (a) a gasphase containing the alkylene oxide reactant and (b) a liquid phasecomprising the alcohols and essentially free of added reaction solvent.16. The process of claim 15, wherein the liquid phase in the reactionzone consists essentially of the alcohol, the catalyst and the alkyleneoxide adduct product.
 17. The process of claim 16, wherein each R is aC₁ to C₆ alkyl moiety.
 18. The process of claim 17, wherein thebimetallic oxo compound is supported on a carrier.
 19. The process ofclaim 17, wherein the reaction zone comprises a liquid phase which issolvent-free and consists of the process reactants, catalyst andproducts.
 20. A process for the preparation of ethylene oxide adducts ofacyclic aliphatic primary alcohols which comprises contacting andreacting ethylene oxide with one or more C₈ to C₂₀ monohydric acyclicaliphatic primary alcohols in the presence of between about 0.2 and 1.0percent by weight, calculated on alcohols, of a catalytically effectiveamount of a bimetallic oxo compound of the formula (RO)_(n)M--O--M'--O--M(OR)_(n), wherein each R is a C₁ to C₂₀ alkyl moiety, M'is a divalent metal selected from the group consisting of vanadium,molybdenum, manganese and tungsten, each M is a trivalent or tetravalentmetal selected from the group consisting of aluminum, titanium, boronand vanadium, and each n is 2 if the adjacent M is trivalent or 3 if theadjacent M is tetravalent, in a reaction zone which comprises (a) a gasphase containing the alkylene oxide reactant and (b) a liquid phasecomprising the alcohols and no more than about 6 percent by weight,calculated on alcohols, of added reaction solvent.